The fire forced an evacuation of the building for several hours, and a cleanup effort is underway.

Crews measured levels of chemicals such as cyanide and carbon monoxide that were left from the fire's toxic smoke before anyone could re-enter the building. More than 80 industrial air scrubbers were deployed in the building.

"When the call comes in that there's a fire at City Hall and it's at the Police Department and, oh, by the way, we have heavy black smoke, a variety of different things come to mind," said fire Deputy Chief Carl Roediger. "Where is it spreading, what's involved, is it normal combustibles?

Officials said most of the damage was done by heavy toxic smoke from the smoldering rubberized shooting range backstop where the flames first started.

"Some officers, or at least one officer, was using it earlier in the night," said police Deputy Chief Corey MacDonald. "We don't know if that's related or if it has anything at all to do with it."

During the cleanup, the shooting range will be gutted and other ceilings torn out. Every surface of every floor of the building must be cleaned, all while police stay on duty.

"This is a massive impact for us, unfortunately," MacDonald said. "The nature of the fire and the backstop and the stuff that actually burned causes a level of toxicity on the ceilings and the walls and everything it touches, and unfortunately, our range is right next to our locker room, so all the officers' lockers with all of their uniforms, all of our equipment, all have to be professionally cleaned, and it's not like just bringing it to the dry cleaners."

MacDonald said the officers are making do with what they have.

"So, we have some officers out today in jeans," MacDonald said. "We're trying to make them look as professional as possible while not having uniforms."

MacDonald said police are working with firefighters to uncover the cause of the fire so they can determine whether any protocols need to be changed.

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